496 Mag Exhaust Manifolds, Performance?

[Sweet Addiction]

Now, if we could just get someone to install the Lightning kit! I would be the first, but I have got to get the stereo done first.
Your up next, I know you have been thinking about it.

[shadow]

Alright guys, I am running a 26' checkmate with a 496 mag and I installed my EMI exhaust over the weekend and went for a run on Sunday, 75 gal tank little over 3/4 full and 4 adults on board.
So before I was Complaining about the fact that when I had my prop labbed at the shop that I lost about 200 RPM and it felt quite sluggish. I was only able to get a GPS at about 60 maybe 61 and was only running 4600 RPM
After the exhaust was installed, I noticed a deeper sounding engine that seemed to breath better during idle, the hole shot was better, and holy shit mid range will throw you back in your seat.
Although the wind was kicking up into the mid 20's and creating 3-4 swells I still got some driving time in.
I definately had a smile on my face.
So the best I could get today was 4800 RPM, 63.5 mph on the GPS, and the water conditions were crappy.
Plus I am going to take the prop back in do a little adjustment to bring it back down 100 RPM to 4700 and I think I will see a constant 65 mph I hope.
I am happy with them, the install went great except for the damn plugs on the bottom, and it looks good in the engine compartment.
So, thats about all the updates I have for now, Hope this helps some of you guys.
Oh, sorry I did not go run again with the stockers to verify.
Congrats on getting your new exhaust installed,I hope you get all the gains expected.
Now let me ask you this?If you were only spinning 4600 rpm before and now getting 4800 rpm,Why would you want to get your prop worked to get you back down to 4700 rpm.
If i'm understanding this correctly you are defeating the whole purpose of installing new exhaust system. Why not install the correct prop to get you up around 5000 rpm-5200rpm?A prop that gets you into this range is going to
be most effient.Not to mention will also feel like you just added some more upgrades. Like i said,i'm just curious here maybe i'm not understanding.

[Beer-30]

Congrats on getting your new exhaust installed,I hope you get all the gains expected.
Now let me ask you this?If you were only spinning 4600 rpm before and now getting 4800 rpm,Why would you want to get your prop worked to get you back down to 4700 rpm.
If i'm understanding this correctly you are defeating the whole purpose of installing new exhaust system. Why not install the correct prop to get you up around 5000 rpm-5200rpm?A prop that gets you into this range is going to
be most effient.Not to mention will also feel like you just added some more upgrades. Like i said,i'm just curious here maybe i'm not understanding.
Remember, Shadow, he is a Mag, not an HO. His rev limit it what - 4850, 4950?
Still, you're right. I think he should find a prop that hits the limiter and then back it down from there.

[THOR]

I got here a little late guys and am going through this same stuff right now. I am seriously considering having my ECM recalibrated through Whipple. Through their testing they report 28-42 HP increases with that alone. Also, why not get the upgrading air intake through AZ Speed and Marine. That reports about 10 HP. These seem like easy HP gains without doing any motor work.

[Beer-30]

I got here a little late guys and am going through this same stuff right now. I am seriously considering having my ECM recalibrated through Whipple. Through their testing they report 28-42 HP increases with that alone. Also, why not get the upgrading air intake through AZ Speed and Marine. That reports about 10 HP. These seem like easy HP gains without doing any motor work.
What intake kit from AZSM? All there is for the 496 is a K&N. If you are referring to the MSD box, K&N, and fuel pressure regulator, that would be for 454-502s only. Not 496.

[phebus]

AZSM now offers their flame arrestor for the 496

[Beer-30]

AZSM now offers their flame arrestor for the 496
Ok, still no real HP to be gained there. I didn't notice any. I just was curious about the 10HP.

[phebus]

When I switched to the K&N, I didn't notice any gains in speed or rpm. I kept the K&N on for the filtering abilities.
You can see right through the screen arrestor that is stock, so I don't think any filter would flow any more air.

[Beer-30]

When I switched to the K&N, I didn't notice any gains in speed or rpm. I kept the K&N on for the filtering abilities.
You can see right through the screen arrestor that is stock, so I don't think any filter would flow any more air.
Yeah, I was same as you in this respect. I added it about the same time and even posted pics of the crap that was in my inlet bell. I didn't notice any performance gain. Just peace of mind in filtering.

[THOR]

AZSM uses the KN but I remember reading somewhere that it added a few HP. I forget where though.
Either way, I think I will be getting my ECM reprogrammed to gain some extra HP.